Visual Ecology &Evolutionary Physiology

How and Why Do Eyes Evolve?Amid the wide diversity of eyes found in different animals, the shell-eyes of chitons (Mollusca: Polyplacophora) may be the most unusual of all. Most chitons lack eyes as adults, but certain species have hundreds to thousands of tiny (< 100 micron), image-forming eyes embedded in their protective shell plates. These are the first eyes known to form images using lenses made of the mineral aragonite (CaCO3). Questions we are asking about these eye include: What are the functional advantages and/or constraints associated with lenses made of shell? Why do most species of chiton lack eyes? What are the genetic components of these eyes and what were the genetic changes associated with their origin? To what degree do the nervous systems of chitons integrate information collected separately by their hundreds of eyes?

Research Areas

VisualEcology

Most animals with eyes have a pair of them on their head. However, some animals -- such as certain bivalves and chitons -- have dozens to hundreds of separate eyes distributed across their bodies. What behaviors do these eyes influence? How may the visual world appear to these unusual animals?

Evolution ofComplex Traits

How and why do new complex traits -- such as jet-propelled swimming in scallops or metal-coated teeth in chitons -- evolve? To seek answers, we identify the structural and genetic components of these traits and ask how, why, when, and in what order they came to be associated.

Comparative Neurobiology

Recent instances of eye evolution in mollusks may help us learn about the co-evolution of sensory systems and neural structures. For example, scallops are unusual among bivalves for having sophisticated eyes, a wide range of light-influenced behaviors, and a relatively complex nervous system.